Chapter 8. Digital I/O

8.1 Introduction

The Güralp Affinity has a number of hardware lines that are typically used for power monitoring and supply, tamper detection, although they are available for other purposes if desired. These lines are monitored and controlled via the digital I/O page of the web interface. General use of this page is described in the Platinum manual.

The following section lists the available lines and described the purpose of each.

8.2 Lines

8.2.1 Auxiliary power output

This output is presented on pin D of the POWER connector (see section 5.2.2.3). It provides the same voltage as the main input power supply and is protected by a 550 mA fuse.

8.2.2 Auxiliary power output B

This output is only exposed in OBS packages. It provides the same voltage as the main input power supply and is protected by a 550 mA fuse.

8.2.3 Ethernet auxiliary power output

This output is presented on pin D of the ETHERNET connector (see section 5.2.2.2). It provides the same voltage as the main input power supply and is protected by a 550 mA fuse.

8.2.4 GPS Port

This output is intended to power the GPS receiver. It is presented on pin B of the GPS connector (see section 5.2.2.5). It provides the same voltage as the main input power supply and is protected by a 550 mA fuse.

8.2.5 GPS Port detect

This “input” is connected to an RS232 detector at the NMEA input of the GPS port. It is driven high when an RS232 device is detected at pin K (see section 5.2.2.5).

8.2.6 System

This input monitors the main power supply input to the Affinity and displays the voltage being received and the current being drawn.

8.2.7 Tamper line 0

This “input” is driven by the outputs of an internal photo-detector and two micro switches which act together to indicate whether the casing has been opened. It is typically used to affect the status of the authentication_seal_broken and/or digitizing_equipment_open security bits in CD1.1 packet headers.

8.2.8 Tamper lines 1, 2 and 3

These three independent inputs are exposed on pins F+L, E and D of the GPIO connector (see section 5.2.2.6). Pins F and L are both connected to tamper line 1. They are typically used as tamper-detection inputs and their status can be mapped to appropriate security bits in CD1.1 packet headers.

8.2.9 USB high-power output

This output is only exposed in OBS packages. It provides the same voltage as the main input power supply and is protected by a 550 mA fuse.

8.2.10 Internal USB port

This switchable power output is internally connected to the power input of the internal USB memory device.

8.2.11 External USB port

This switchable power output is intended to power external USB devices such as memories. It is presented on pin A of the USB connector (see section 5.2.2.4). It provides 5 V DC, in accordance with the USB standard.

8.2.12 External USB port (peripheral mode)

This input is driven by the USB on-the-go detection on pin F of the USB connector (see section 5.2.2.4). This is an experimental feature which has no current application.